Prevent manually changing excel file extension in windows explorer

[MrC54]

Hey all,

New to the group. I found the code to prevent saving of my file to anything other than xlsb, but how do you stop someone from changing it manually in windows explorer?

Background info...trying to stop a smarty pants from hacking my password protected file. One trick is to change the extension to zip and backdoor it.

Ultimately, I want to make my document hack proof to office folk that know their way around "some" code, but not enough to be effective against something more sophisticated.

Any help would be greatly appreciated! Thank you!

 

[Jeffrey Mahoney]

Keeping your password in VBA stored as a string of encrypted ASCII characters and the locking the VBA will prevent them from running your code. The smarter hackers will be able to break into the sheets. People can create code to make sheets visible that are XLVeryHidden from another workbook VBA. Data and formulas are less protectable. If you really need to prevent someone from accessing data, don't put it in a workbook.

There are 255 characters in the standard ASCII character set. Find a mathematical way of turning your provided password into a set of ASCII characters embedded in a longer string of ASCII characters. You can put over 32,000 characters in a single cell. So, if you want to store that password where every 593rd character is the actual password, how long do you think it will take them to break it?